1. Field of the Invention
Modern internal combustion engine design is undergoing important changes to meet stricter standards concerning engine and exhaust gas emissions. One major change in engine design is the feeding of blow-by gases from the crankcase zone of the engine into the intake air-fuel mixture at the carburetor just below the throttle plate, rather than venting these gases to the atmosphere as in the past. The blow-by gases contain substantial amounts of deposit forming substances and are known to form deposits in and around the throttle plate area of the carburetor. Another significant change is the recirculation of a part of the exhaust gases to the fuel air intake of the engine. These exhaust gases also have deposit forming tendencies. The deposits caused by the recirculated gases, both blow-by and exhaust gases, restrict the flow of air through the carburetor at idle and at low speeds so that an over-rich fuel mixture results. This condition produces rough engine idling and stalling and leads to the release of excessive hydrocarbon exhaust emissions to the atmosphere.
The noted design changes while effective for prompting a cleaner exhaust from the engine also leads to a fouling of the carburetor and therefore dictates the need for an effective detergent fuel composition in order to maintain the cleanliness and efficiency of the carburetor.
2. Description of the Prior Art
U.S. Pat. No. 3,980,450 discloses a carburetor detergent compound of the formula: ##STR1## where R is a hydrocarbyl group containing at least 20 carbon atoms, R.sup.1 is a hydrocarbyl or amino substituted hydrocarbyl group and R.sup.2 and R.sup.3, which may be the same or different, are hydrogen atoms or alkyl groups and a gasoline composition containing same.
U.S. Pat. No. 3,849,083 discloses a gasoline containing a carburetor detergent amount of ether amine selected from:
I. R--O--L--NH.sub.2 PA1 II. (R--O--L--).sub.2 NH and PA1 III. mixture containing (I) and (II)
wherein R is selected from C.sub.1 -C.sub.40 alkyl groups, C.sub.6 -C.sub.40 aryl groups and C.sub.3 -C.sub.40 alkenyl groups, and L is C.sub.2 -C.sub.8 alkylene, and additive concentrates suitable for blending into gasoline containing said ether amine detergent.
U.S. Pat. No. 3,309,182 discloses polyether diamines as inhibitors of sludge sediment formation in petroleum distillate fuels.